Pelger-Huet Anomaly

Pelger-Huet Anomaly is a hematologic disease characterized by developmental abnormality of granulocytes, a type of white blood cells. Abnormal granulocytes have ovoid shape nuclei and clumping chromatin which interferes with their normal function. Matings between two animals with Pelger-Huet anomaly may result in smaller litter sizes because the homozygous form of the anomaly is usually lethal in prenatal animals. In the unlikely event when affected puppies or kittens survive, they may exhibit osteochondrodysplasia marked by severe skeletal deformities and increased susceptibility to infection.2 The congenital form of this disease has been described in humans, dogs, rabbits and domestic shorthair cats. The canine cases have been mostly observed in the Australian Shepherd, Coonhound, and Foxhound breeds. In the majority of dogs twith Pelger-Huet anomaly, correct and timely diagnosis of this disorder may avoid unnecessary and expensive laboratory testing as well as improper drug administration for presumed infection or developing leukemia.

An acquired form of Pelger-Huet anomaly is referred to as seudo Pelger-Huet anomaly which is characterized by the inability of white blood cells to mature in a normal way. Pseudo Pelger-Huet anomaly is similar to congenital anomaly, but is acquired and transient. The condition may occur during a severe infection, leukemia, or unknown causes. Rarely, this form of the disease can occur following administration of certain drugs or in animals with myeloproliferative disorders.4